Improved Wireless, Transcutaneous Power Transmission for In Vivo Applications

Electric power, sufficient for many in vivo applications, can be transmitted wirelessly from a small external solenoid (filled with a soft magnetic core), to a novel, magnetoelectric (ME) receiver a few centimeter (cm) inside the body. The ME receiver is a sandwich of electroactive (e.g., piezoelectric) material bonded between two magnetostrictive layers. The electroactive layer may be poled in its plane so that it can function in the stronger g 33 mode (induced voltage parallel to the direction of principal magnetostrictive stress). Preliminary experimental results indicate that a 7 cm long ferrite-filled solenoid (NI ap 122 Amp-turns) producing an RMS magnetic field of order 1600 A/m (20 Oe) at the ME receiver (of volume 0.1 cm 3 ) 3 cm from the field source, generates in the ME receiver a power of 200 mW (2 W/cm 3 ). The receiver, in turn, generates a power of 160 mW.